1. Field of the Invention
This invention relates generally to antennas, and more particularly to the mounting of an auxiliary terrestrial and/or satellite antenna on a reflector antenna.
2. Description of the Prior Art
Satellite dish or reflector antennas have gained popularity, in part, for their ability to provide television programming from a number of sources greater than that available from local, terrestrial VHF and UHF stations. However, such dish antennas are adapted to receive video signals from satellites disposed in synchronous or stationary orbits about the earth to the exclusion of locally transmitted VHF and UHF signals. To enable reception of locally transmitted video signals and locally produced television programs, it is necessary to also employ an antenna that is adapted to receive signals in other bands, such as VHF and UHF.
U.S. Pat. No. 5,606,334 to Amarilllas, et al. is directed to the combination of a compact, rectangularly-shaped assembly of a reflector or dish antenna with fragmented curved surfaces and a VHF/UHF antenna, which is mounted on the reflector. An amplifier processes the signals from the reflector and its waveguide. The VHF/UHF antenna is mounted along the periphery of the reflector.
U.S. Pat. No. 5,793,336 to Shoemaker, et al. is directed to the combination of two antennas. The first antenna includes a nonconductive layer, on which first and second radiators are deposited. The second antenna is a double-curved dish. The first antenna is disposed in a housing, which includes a back plate. The plate is mounted to the back of the double-curved dish.
Neither of the patents discussed above deals with the needs or problems presented by the after-market, where it is often desirable to retrofit dish antennas that have already been installed. Of course, a second antenna could be installed at the expense of the aesthetic appearance of the structure, e.g., a residence, to which two antennas are mounted.
In U.S. Pat. No. 5,929,818 to Snyder, an assembly having a dish antenna and a UHF/VHF antenna, which includes two dipoles, is disclosed. The dipoles are bent into a shape that is similar to that of the dish.
The television signals from the satellite source and the terrestrial source are outputted from the satellite dish antenna and the UHF/VHF antenna, respectively. The television signals may be transmitted by coaxial cable in a variety of ways to a satellite receiver. The satellite receiver is disposed within a building or home, on which the antenna assembly is mounted. As is well known in the art, the satellite receiver performs a number of functions. First, the receiver demodulates the television signal before feeding it to the display for viewing. Second, the satellite receiver provides a selective switching function, which enables the viewer to select which of the satellite or terrestrial signals is to be displayed.
In one mode, two coaxial cables are coupled between the satellite receiver and the antenna assembly. In a second mode, a pair of diplexors enables a single coaxial cable to carry both satellite and terrestrial signals to the satellite receiver. In this mode, the cable from the UHF/VHF antenna is coupled to the UHF/VHF terminal of the diplexor, and the cable from the satellite dish antenna is coupled to a satellite terminal on the diplexor.
Amplifiers are available to improve fringe area reception of the UHF/VHF transmission signal. It is to be appreciated that the satellite receiver is designed to provide sufficient amplification to the satellite television signal without the use of an additional amplifier. Where two coaxial cables are used to transmit the terrestrial and satellite signals to the satellite receiver, a UHF/VHF amplifier is inserted in series with the UHF/VHF cable. Where only a single cable is used to carry the terrestrial and satellite signals and two diplexors are used, the UHF/VHF amplifier is connected in series between the second diplexor, which is disposed within the structure, and the satellite receiver. However, the installation of the diplexors and the UHF/VHF amplifiers is complicated by the use of two cables or, in the alternative, the incorporation of two diplexors. In addition, the method of mounting the UHF/VHF antenna to the dish antenna disclosed in the Snyder patent does not permit it to be easily removed from or relocated on the dish antenna without a significant amount of effort by the consumer.
It is an object of the present invention to provide an antenna subassembly that can readily be mounted to and repositioned on a dish antenna.
It is a further object of the present invention to provide an antenna subassembly in which one or more different types of satellite and/or terrestrial antennas can be magnetically mounted to a dish antenna in user-selectable orientations with respect to the dish antenna.
It is still a further object of the present invention to provide an antenna assembly that can be connected to a satellite receiver using a minimum number of cables without requiring additional electrical and/or mechanical devices.
It is yet a further object of the present invention to provide an antenna assembly including one or more different types of satellite and/or terrestrial antennas magnetically mounted to a dish antenna in user-selectable orientations with respect to the dish antenna.
In accordance with the present invention, an antenna assembly includes a dish antenna having a reflector, a support magnetically affixed to the reflector, and an auxiliary or second antenna affixed to the support. The reflector has a front signal-receiving surface and a rear surface. At least a portion of the rear surface is metallic or capable of magnetic attraction. At least a portion of the support is also metallic or magnetic. The auxiliary antenna is coupled to the support, which enables it to be removably affixed and selectively positioned on the reflector via magnetic attraction between the support and the rear surface of the reflector. An adjustable mounting device, such as a captive-ball mount, may be disposed between the support and the auxiliary antenna to permit additional selective positioning of the auxiliary antenna in at least one plane. The antenna assembly may also be a subassembly, which preferably includes only the support and the auxiliary antenna. Such an antenna subassembly may be used to retrofit existing dish antennas.
In further accordance with the present invention, an antenna subassembly includes the auxiliary satellite and/or terrestrial antenna, a power amplifier, and a diplexor. The auxiliary antenna receives and outputs an auxiliary video signal. The power amplifier has an input connected to the auxiliary antenna to receive and amplify the auxiliary video signal. The diplexor has first and second input terminals and an output terminal. The second input terminal is connected to the power amplifier and receives the amplified auxiliary video signal. The first input terminal is preferably connected to the satellite dish to receive the satellite video signal. The diplexor sums the amplified auxiliary signal and the satellite video signal and transmits the aggregate signal in a first direction to its output terminal. In addition, the output terminal of the diplexor preferably receives a power signal and transmits the power signal in a second direction, which is opposite to the first direction, via the first input to the power amplifier. The power signal is used to energize the power amplifier.
In further accordance with the present invention, the antenna subassembly includes a second diplexor, and first and second sensors for outputting, respectively, first and second satellite video signals. The second diplexor includes third and fourth input terminals and a second output terminal. The first and third input terminals are preferably connected to the first and second sensors to receive, respectively, the first and second satellite video signals. The power amplifier is connected to each of the second and fourth input terminals to apply thereto the amplified auxiliary video signal. Thus, the first and second diplexors transmit first and second aggregate signals in a first direction to the first and second output terminals, respectively. Preferably, at least one of the first and second output terminals receives a power signal and transmits the power signal in a second direction to the power amplifier, which energizes the power amplifier.
These and other objects, features and advantages of the present invention will become apparent from the following detailed description of illustrative embodiments thereof, which is to be read in connection with the accompanying drawings.